But as night fell Saturday, more than 2,000 spectators filed into the 2nd Street tunnel in downtown Los Angeles to cheer on riders. With their heads down and legs pumping as fast as they would go, the cyclists blazed through the tunnel in pairs at a pace that reached well over 30 miles per hour.

The best of the riders didn’t even have brakes — slowing down was not their concern.

“You just give it all you can, just pedal as fast as you can,” said 29-year-old Mike “The Cheetah” Chitjian of Monterey Park, who was one of about 200 participants. “Your legs hurt, but you just block out the pain.”

There have been bicycle drag races in the city before, but what made Saturday night’s event unique was that it was legal, permitted, and endorsed by city officials and the police.

That’s a big change for bicycle groups like Wolfpack Hustle, which created the event, because they have not always played by the rules of the road. For example, they have sometimes treated red and green traffic lights the same and have seldom — if ever — sought permission for their rides.

“We’re not trying to be outlaws,” said Don Ward of Wolfpack, who is known as Roadblock and was the event’s lead organizer. “We’re just trying to get our bodies in shape.” He hopes “The Midnight Drag Race: Codename ‘The Final Effin Sayso’ ” will become an annual event.